CA2027507C - Artificial stone compositions, process of producing the same and apparatus employed in the production thereof - Google Patents

Abstract

A molding composition which, when cured, is useful as an artificial stone composition, is disclosed. The composition comprises between about 10 to about 25 parts by weight of a non-volatile polyester backbone resin; between about 10 to about 25 parts by weight of an ethylenically unsaturated monomer and between about 50 to about 80 parts by weight of a filler selected from the group consisting of alumina trihydrate, borax, hydrated magnesium calcium carbonate and calcium sulfate dihydrate. When an artificial stone composition simulating granite is desired, the molding composition further comprises chips of a previously cured thermosetting resinous composition. The compositions are produced in a vented but essentially closed mold through which heating and cooling media can freely flow.

Description

~ ~ ~ 15 0 ~ DK-9063-M45 1 TITLE: ARTIFICIAL STONE COMPOSITIONS, PROCESS OF

2 PRODUCING THE SAME, AND APPARATUS EMPLOYED

4 INVENTORS: GERALD BRUCKBAUER, ET. AL.

SPECIFICATION
6 Back~round of the Invention 7 This invention relates to artificial stone compositions 8 including those simulating marble and granite, processes of 9 preparing articles therefrom, and apparatus employed in the production of the same. Such articles may be used in such 11 household, commercial, and industrial applications in which 12 durable decorative surfaces are desired, such as as kitchen 13 countertops, table tops and bathroom vanities.
14 The prior art discloses simulated stone compositions and 15 processes of preparing articles therefrom. For example, 16 u.s. Patent No. 4,446,177 and Australian Patent Publication 17 S . N. 8665193 disclose compositions comprising a matrix of 18 polyester and alumina trihydrate. U.S. Patent No. 4, 085,246 19 discloses a simulated granite article comprising alumina trihydrate and polymethylmethacrylate having opaque and 21 translucent particles randomly distributed therein. Further, 22 U.S. Patent No. 4,433,o70 discloses a polishable marble 23 surface comprising a polyester resin derived from isophthalic 24 acid, a glycol and, as cross1in~ing ~lC r, either styrene or methyl methacrylate.
26 The articles disclosed in U.S. Patent No. 4,446,177 were 27 produced by first coating a polyester gel coat into a mold 28 and then applying the polyester veining matrix, and, ~a~sd7 1 subsequently, a b~cking layer. See also U.S. Patent No.
24,664,954. Such processes are tedious and render a product 3 having neither uniform cure or uniform color.
4A need exists for an artificial stone composition and a method of making such compositions which when fully cured 6 exhibit uniform satisfactory physical properties. A need 7 also exists for a process of making such compositions which 8 is relatively simple and econ: ical.
9 Summary of the Invention 10The invention is drawn to molding compositions and cured 11 products made therefrom, processes for preparing such 12 products, and apparatus employed in the production of such 13 products. The cured products of this invention simulate 14 stone and are highly useful in the manufacture of durable decorative protective surfaces.
16The thermosettable molding composition of this invention 17 comprises a non-volatile polyester b~c~ho~e resin and an 18 ethylenically unsaturated - ~ -r in a ratio of from about 191:2.5 to about 2.5:1 parts by weight. In the preferred ~ iment, a filler is included such that the composition 21 comprises between about 10 to about 25 parts by weight of a 22 non-volatile polyester backbone resin; between about 10 to 23 about 25 parts by weight of an ethylenically unsaturated 24-r- r and between about 50 to about 80 parts by weight of a filler, preferably a hydrated mineral selected from the group 26 consisting of alumina trihydrate, borax, hydrated magnesium 27 calcium carbonate and calcium sulfate dihydrate. Such ~0 '7507 1 compositions when cured simulate artificial stone such as 2 marble.
3 A second molding composition of this invention contains, 4 in addition to the thermosettable composition recited above, discrete chips. Such chips may be the fully or partially 6 cured product of the thermosettable molding composition of 7 this invention or may be chemically distinct therefrom. When 8 cured, such second molding compositions simulate such 9 artificial stone such as granite and onyx.
The invention further includes a process of preparing 11 such artificial stone compositions which comprises mixing a 12 resinous composition comprising a polyester; one or more 13 ethylenically unsaturated ~n~ -rs; catalyst, accelerator, 14 promoter or other curing agent; colorant, if desired; and filler, if desired (and, when simulated granite or onyx is 16 desired, chips of an inorganic material or of a partially or 17 fully cured synthetic resin such as the molding composition 18 of this invention); de-aerating the mixture; flowing the 19 mixture under airless conditions into a vented but essentially ciosed mold defined by a boundary frame and by 21 platens through which heating media flows; and partially or 22 fully curing the composition in the mold. If desired, curing 23 can be completed outside the mold cavity, in an oven or in a 24 platen press which may correspond in configuration to the mold, or which may further mold the partially cured 26 composition to an altered configuration.

~o irlsa7 1 The invention further provides a mold bounded by platens 2 suitable for use in the production of artificial stone 3 compositions with a means of uniformly regulating the 4 temperature during the curing stage.
Brief Description of the Drawin~s 6 Fig. 1 is a diagram of the components of the system used 7 to perform the process according to the invention;
8 Fig. 2 is the diagram of Fig. 1, showing in dotted lines 9 one process flow alternative;
Fig. 3 is the diagram of Fig. 1, showing in dotted lines 11 a second alternative flow scheme;
12 Fig. 4 is the diagram of Fig. 1, showing in dotted lines 13 a third alternative flow scheme;
14 Fig. 5 is the diagram of Fig. 1, showing a fourth alternative flow scheme;
16 Fig. 6 is an exploded side elevation of a boundary frame 17 between two platens creating a single cavity mold from the 18 multiple mold assembly shown in Fig. 7;
19 Fig. 7 is a top plan view of a five-cavity platen assembly;
21 Fig. 8 is a side elevation view of the platen assembly 22 of Fig. 7;
23 Fig. 9 is a front elevation view of the platen assembly 24 of Fig. 7;
Fig. 10 is a side elevation view of the platen assembly 26 of Fig. 7, showing in dotted lines pistons for moving the 27 individual platens;

~027507 1 Fig. 11 is a front elevat ~ f the platen assembly 2 of Fig. 7, showing the boundary frames between the platens;
3 Fig. 12 is a perspective view of the inlet valve 4 assembly of the mold assembly;
Fig. 13 is a perspective view of the riser projection of 6 the mold shown in Fig. 6; and 7 Fig. 14 is a front elevation view of the platen assembly 8 of Fig. 7, showing the boundary frames and press plates 9 between the platens.
Detailed Description of the Invention 11 The composition of this invention is drawn to a 12 synthetic resinous system which when fully cured simulates 13 stone. Such cured compositions exhibit a Flame Spread Index 14 (ASTM E84-87) less than 25.0 and a Smoke Index (ASTM E84-87) less than 25.0, and a Barcol hardness of greater than about 16 50. Barcol hardness is measured by a Barcol impresser, U.S.
17 Pat. No. 2,372,662, manufactured by Barber-Colman Co., 18 Rockford, Illinois, Part No. 934-1. The Barcol hardness 19 scale is linear. A Barcol value of 0 indicates a 30 mil penetration by the impresser's test probe. A Barcol value of 21 100 indicates no measurable penetration. Surfaces suitable 22 for table top and countertop applications should have a 23 Barcol value of at least 55.
24 The first molding composition of this invention comprises a non-volatile polyester backbone resin and an 26 ethylenically unsaturated ~n~ or in a ratio of from about 27 1:2.5 to about 2.5:1 parts by weight. Examples of such $ ~ '' 1 compounds, and methods of their preparation, are set 2 forth in U.S. Pat. No. 3,980,731. It is preferred that a filler be included in the composition, such that the ultimate composition comprise between about 10 to about 4 25 (most preferably 14 to 18) parts by weight of a non-5 volatile polyester, between about 10 to about 25 (most preferably 15 to about 22) parts by weight of an ethylenically unsaturated monomer, and between about 50 7 to about 80 (most preferably between about 60 to about 8 70) parts by weight of a filler.

11 When an acid that contains more than one -COOH group 12 reacts with an alcohol that contains more than one -OH group, 13 the product is a polyester. The reaction is called 14 condensation polymerization, since -r~f or molecules are combined with the loss of simple molecules such as water or 16 methanol.
17 A generally rigid polyester is desired, formed of highly 18 cross-linked molecules rather than linear molecules of the 19 sort valuable in the manufacture of polyester for fiber applications. The polyester employed in the composition of 21 this invention is preferably a polycondensation product of 22 polycarboxylic acids including the dicarboxylic acids (as 23 herein defined) and polyhydric alcohols. Preferably, the 24 polyester is derived from at least two dicarboxylic acids and at least one glycol. Most preferably, at least one of the 26 dicarboxylic acids is an acyclic ethylenically unsaturated 27 acid. Such dicarboxylic acids include those selected from ,,~

~027507 1 the group consisting of maleic, fumaric, linoleic, linoleic, 2 itaconic, sebacic, tartaric, tetrachlorophthalic and oleic 3 acid and anhydrides thereof. Maleic anhydride is especially 4 preferred because of its availability. The other dicarboxylic acid is aromatic and is most preferably either 6 isophthalic, adipic, azelaic, phthalic acid or anhydrides 7 thereof. Most preferred is isophthalic acid, because it 8 lends greater chemical resistance to the molded product.

9 Adipic acid may be used when a more flexible product is desired.
11 The glycols which react with the dicarboxylic acids to 12 form the polyester are preferably selected from at least one 13 C2-C8 glycol and include neopentyl glycol, 14 1,4-butanediol, ethylene glycol, diethylene glycol, propylene glycol, dipropylene glycol, 1,3- and 2,3- butylene glycol, 16 butylene trimethylene glycol, 1,6-hexAne~iol, 17 1,4-cyclohexanediol, and triethylene glycol. The polyester 18 bAc~hone is produced under condensation reaction conditions 19 well known in the art.
Suitable ethylenically unsaturated - - rs for reaction 21 with the polyester include alkyl acrylates and methacrylates 22 wherein the alkyl groups comprise from 1 to about 18 carbon 23 atoms, preferably between 1 to about 4 carbon atoms.
24 Suitable acrylic ~n~ -rs are methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, n-propyl 26 acrylate, n-propyl methacrylate, i-propyl acrylate, n-propyl 27 methacrylate; n-butyl, 2-butyl, i-butyl and t-butyl acrylates h a h ~ 5 0 7 1 and methacrylates; 2-ethylhexyl acrylate and methacrylate;
2 cyclohexyl acrylate and methacrylate; hydroxyalkyl acrylates 3 and methacrylates; N,N-dialkylaminoalkyl acrylates and 4 methacrylates; and N-[t-butyl]aminoethyl acrylates.
Other ethylenically unsaturated monomers include such 6 preferred compounds as styrene, vinyl toluene, vinyl acetate, 7 acrylonitrile, methacrylonitrile, maleic acid, maleic 8 anhydride and esters of maleic acid, acryl amide, 9 methacrylamide, itaconic acid, itaconic snhydride and esters of itaconic acid ~nd other multifunctional lc -rs;
11 alkylene diacrylates and dimethacrylates; allyl acrylate and 12 methaacrylate; N-hydroxymethylacrylamide and N-hydroxymethyl-13 methacrylamide; N,N'-methylene diacrylamide and 14 dimethacrylamide; glycidyl acrylate and methacrylate; diallyl phthalate; divinylbenzene; p-tert butylstyrene;
16 divinyltoluene; trimethylolpropane triacrylate and 17 trimethacrylate; pentaerythritol tetraacrylate and 18 tetramethacrylate; triallyl citrate and triallyl cyanurate.
19 Two or more of the above ~n~ rs may be combined to be the "ethylenically unsaturated ~r~ ?r" referred to herein.
21 Styrene, vinyl toluene, diallyl phthalate, vinyl acetate, and 22 methyl methacrylate are preferred. Particularly preferred 23 are a combination of styrene and methyl methacrylate, most 24 preferably wherein the weight ratio is between from about 2:1 to about 1:4, respectively, and most preferably between from 26 about 1:1 to about 1:2. If it is desired to reduce the rate 27 of reaction, a small amount (from about lOppm to about 500 ~a~75~7 1 ppm) of an inhibitor, such as methyl ethyl hydroquinone, can 2 be included in the reaction mixture to initially inhibit the 3 reaction of the methyl methacrylate.
4 Matrix fillers may be any materials which yield the desired visual, chemical, and physical properties in the 6 molded product. When a product of homogeneous appearance is 7 desired, the filler should be sufficiently small in particle 8 size, and be sufficiently dispersed in the matrix, that 9 discrete particles or agglomerates of particles are not visible. When a product bearing the speckled appearance of 11 granite is desired, the size, configuration, and 12 concentration of the filler particles is a matter of choice 13 dependent on the desired visual, chemical, and physical 14 characteristics of the molded product. Preferably, for a granite appearance, a visually indistinct matrix filler is 16 employed, as well as visible discrete chips of resinous 17 material which themselves include filler particles.
18 When a product with less visually distinct filler 19 characteristics is desired, such as a product bearing the appearance of striated marble, a visually indistinct matrix 21 filler is employed, as well as pigmented or unpigmented resin 22 in uncured or partially cured semi-liquid form to form the 23 striations.
24 The composition of the filler also affects the physical and chemical properties of the molded product, such as 26 physical strength, stain resistance, hardness, and fire 27 retardancy. The filler may comprise any material which is, _ g _ ~75~
1 or can be made, compatible with the reactive materials, and 2 which imparts the desired characteristics to the molded 3 product. Satisfactory fillers include inert inorganic or 4 organic material, such as finely ground stone, talc, mica, wollastonite, kaolin, silica, calcium carbonate, calcium 6 sulphate, glass (spheres and fibers), metals, antimony oxide, 7 or resin of the type comprising the composition of this 8 invention.
9 In a molded product in which fire retardancy is of concern, the matrix fillers can comprise materials such as 11 halogenated compounds and metal oxides, which decompose to 12 deprive the flame front of oxygen; antimony trioxide or 13 antimony pentoxide; polybrominated diphenyloxides;
14 organophosphorous compounds; antimony-halogen-molybdenum systems; and alumina trihydrate. Preferred are materials 16 which are capable of releasing water molecules at moderately 17 elevated temperatures of from about 300~F to about 18 700~F. Such fillers include compounds which chemically 19 bind water molecules, such as alumina trihydrate (aluminum hydroxide) and other hydrated materials capable of releasing 21 water molecules when heated. Such fillers also include 22 borax, hydrated sodium borate, hydrated magnesium, calcium 23 carbonate and calcium sulfate dihydrate. Alumina trihydrate 24 is especially preferred.
If smoke suppression is desired, the fillers can 26 comprise alumina trihydrate, magnesium oxide, zinc oxide, 27 borates, and molybdenum compounds.

~a~7~7 1 Alternatively, to provide fire retardancy and/or smoke 2 suppression, water may be bound physically rather than 3 chemically in the filler. For example, such fillers include 4 hollow glass beads filled with water, and polymers having water molecules physically bound within their interstices.
6 It is generally preferred to maximize the loading of 7 filler particles in the composite, because the filler is 8 usually less expensive than the resin, and because some 9 properties, such as fire retardancy, are partly a function of filler loading. The ny; loading is usually a function of 11 the viscosity of the molding composition, and the 12 desirability of ensuring that all filler particles are coated 13 with resin. With a given particle size distribution, as 14 filler loading increases, the composition increases in viscosity and bec- ~s more difficult to handle and is less 16 likely to conform to mold configurations. For a product 17 resembling marble, the preferred composition comprises, based 18 on weight, from about 10% to about 25% polyester resin, from 19 about 5% to about 12% styrene, from about 5% to about 12%
methyl methacrylate, and from about 51% to about 80% alumina 21 trihydrate. For such a product, the most preferred 22 composition, based on weight, comprises about 12% to about 23 18% polyester resin, from about 5% to about 7% styrene, from 24 about 7% to about 11% methyl methacrylate, and from about 62%
to about 76% alumina trihydrate.
26 The filler particle size and configuration affects the 27 viscosity of the molding composition during operation, the ~ 75 07 1 visual characteristics of the product, the amount of filler 2 that can be employed, and the internal strength and stain 3 resistance of the cured product. Particles larger than about 4 50 microns in length are visible to the naked eye. The 5 filler particle size for a homogenous-appearing marble-like 6 product is usually desired to be a maximum of about 25-30 7 microns in length. In addition, when a white or light 8 colored composition is desired, it is preferred to filter the 9 composition at least once prior to introduction to the mold, to remove visible cont~ in~ntS. The filters are preferably 11 sized to remove particles larger than about 50 microns, and 12 most preferably, larger than about 40 microns. For these 13 reasons, the filler particles will preferably range from 14 about 0.1 to about 40 microns. The mean filler particle 15 diameter is preferably between about 5 to about 20 microns, 16 with particles at least as small as 0.5 microns and at least 17 as large as 30 microns. A particle size distribution which 1.8 allows the largest proportion by volume of particles within a 19 given volume of molded product is preferred (ie., which allows smaller particles to substantially fill the 21 interstices between larger particles), because it allows a 22 higher loading of filler particles at workable composition 23 viscosities. It is preferred that at least about 5% of the 24 particles be larger than about three times the mean particle 25 size, and at least about 5% of the particles be smaller than 26 about one-third the mean particle size. Distributions have 27 been found effective in which about 5% of the particles have ~27507 1 been greater than about ten times the mean particle size and 2 about 5% of the particles have been less than about one-tenth 3 the mean particle size. A generally bell-shaped particle 4 size distribution is most preferred.
It is understood that in referring to the filler as 6 comprising particles, configurations such as fibers (eg., 7 chopped glass fibers) are included. In particular, in 8 applications in which strength is particularly desired, 9 fibrous fillers are desirable.
A molded product simulating a hetrogeneous-appearing 11 material such as granite or onyx, comprises discrete visible 12 chips distributed throughout a matrix. Such a product may be 13 made from a molding composition comprising a matrix of the 14 thermosettable molding composition set forth in detail above, within which are dispersed discrete chips of a previously 16 partially or fully cured resin or of some other material 17 generally compatible with the molding composition (either by 18 themselves, by coating the chips with ~ or, or by 19 application of a conventional coupling agent such as silane, found especiAlly useful in melamine and polyester 21 applications). The amount of chips, as well as their shape, 22 size, and composition, are dependent upon the appearance, 23 physical, and chemical characteristics desired of the final 24 cured product. It is preferred that the chips be larger than about 50 microns, since chips smaller than about 50 microns 26 are generally not visually discernable as discrete particles, 27 but rather appear as colorants. The , ny; chip size is b ~ 2 i~ 0 7 1 primarily a function of esthetics. It is preferred to employ 2 chips between about 250 microns and about 25,000 microns.
3 The chips may comprise particulate inorganic material, 4 such as stone particles, chips of a resinous material, pigmented if and as desired, or a combination of such 6 materials. Resinous particles are preferably at least 7 partially cured prior to incorporation into the matrix to 8 maintain the particles visually distinct from the matrix.
9 The chips may also be the cured thermosetting resinous reaction product of the first molding thermosettable 11 composition of this invention. Thus, scrap material 12 resulting from the manufacture of such artificial stone 13 compositions, as for example, artificial marble, may be 14 ground into chips and employed in the production of compositions simulating granite. Preferably, between about 1 16 to about 50 parts by weight of discrete chips of a cured 17 thermosetting resinous system are employed. Most preferably, 18 the weight percentage of chips of the cured resinous 19 composition comprises approximately 2 to about 25 weight percent of the total weight of the second molding 21 c~ -sition. Particularly preferred as the granite 22 composition of this invention is the cured reaction product 23 of the molding composition comprising between about 10 to 24 about 25 parts by weight of non-volatile polyester, between about 10 to about 25 parts by weight of ethylenically 26 unsaturated - ~ -r, between about 50 to about 80 parts by 27 weight of filler and between about 2 to about 25 parts by ~0~ 75 07 1 weight of discrete chips. Most preferred is a composition 2 comprising from about 12 to about 18 parts by weight 3 polyester, from about 5 to about 9 parts by weight styrene, 4 from about 7 to about 11 parts by weight methyl methacrylate, from about 60 to about 70 parts by weight alumina trihydrate, 6 and from about 2 to about 15 parts by weight discrete chips.
7 The physical and chemical properties of the molded 8 product are a function of the properties of both the matrix 9 and the chips. Fire retardancy can be increased by employing chips having a greater flame resistance than the matrix.
11 Inorganic chips, such as stone, may be used. However, 12 although they do not provide fuel, they do not contribute 13 substantially to flame retardancy because they lack the water 14 of hydration for flame extinguishing. Inorganic chips may also be porous, allowing them to absorb foreign materials at 16 the surface of the ultimate product, giving the product low 17 resistance to st~in;ng. In addition, such chips may yield a 18 product with undesirable structural characteristics, which 19 may be relatively easy to fracture, and which may be difficult to polish or cut, because of the substantially 21 different hardness of the chips and matrix.
22 The molding compositions of this invention may be cured 23 by any conventional or convenient means. Polymerization of 24 unsaturated polyester with monomer(s) (eg., styrene and/or methyl methacrylate) can be effected by the use of curing 26 agents which generate free radicals during decomposition, to 27 initate cross-lin~ing of the polyester and the monomer(s).

~Of,7~ ~7 1 Generally, between about 0.15 to about 3.0 weight percent of 2 curing agent based on total weight of the resin (eg., 3 polyester, styrene, and methyl methacrylate) is employed.
4 Suitable curing agents for polyesters and the ethylenically unsaturated ~n; ~rs defined herein are well known in the 6 art.
7 Preferred free radical generators include organic 8 peroxides such as peroxy esters, peroxy ketals, peroxy 9 dicarbonates, diacyl peroxides, h~d~operoxides, ketone peroxides, and dialkyl peroxides. Especially preferred is a 11 mixture of mono-peroxy ester or di-peroxy ester and peroxy 12 ketal. Organic peroxides are prepared by conventional 13 means. See, for example, U.S. Pat. No. 4,052,465.
14 Organic peroxides which act at ambient temperature may be used. Such peroxides are dissociated using promoters or 16 acclerators. Examples are hydroperoxides, ketone peroxides, 17 and some diacyl peroxides. Ketone peroxides and 18 hydroperoxides are usually used with cobalt salts, such as 19 cobalt naphthenate, and cobalt octoates. Diacyl peroxides, such as benzoyl peroxides, are used with aromatic tertiary 21 amines such as diethyl ~niline or dimethyl Aniline.
22 It is desired that substantially no catalyzation occur 23 prior to introduction of the reaction mixture into the mold.
24 For that reason, heat-activated curing agents are preferred to non-heat activated accelerators or promoters. Preferred 26 are those curing agents which are heat activated and capable 27 of functioning in the absence of a non-heat activated 2~7~07 1 accelerator or promoter, and which render a composition 2 having a shelf life of at least 2 hours, and preferably at 3 least 24 hours, at 77 F. Especially preferred are curing 4 agents which are activated by heat in the range of from about 100~F to about 450~F, and preferably from about 150~F
6 to about 250~F, so that substantial catalyzation does not 7 begin until the catalyzed reaction mixture is heated in the 8 mold.
9 Especially preferred is a mixture of a curing agents with a low initiation temperature, between from about 100~F
11 and about 200~F, and a curing agent having a higher 12 initiation temperature, between about 150~F and about 13 250~F. The low initiation temperature curing agent begins 14 the polymerization reaction, which is exothermic. The higher initiation temperature curing agent is activated by the heat 16 of the exothermic reaction, and completes the 17 polymerization. The appropriate ratio of low temperature 18 activated curing agent and high temperature activated curing 19 agent is determined by the desired rates of reaction and the physical p~operties desired of the molded product.
21 Generally, lower temperatures and a slower cure rate produce 22 a product with better physical characteristics, perhaps in 23 part bec~llce a slower rate of reaction produces longer chain 24 polymers. Faster cure rates reduce the time in the mold. IA
general, however, a rapid exothermic reaction reduces control 26 over cure, which can result in stress cracking in the molded 27 part because of non-uniform shrinkage during cure. It is 1 preferred to emploY only sufficient low t~ ,c sture initiated 2 curing agent to generate sufficient heat to activate the 3 second curing agent and to sufficiently polymerize the 4 reaction mixture so that volatile constituents are not vaporized by the heat of the reaction.
6To reduce the amount of time in the mold, it is 7 preferred that the temperature of the composition increase as 8 the polymerization progresses. The ~xi temperature of 9 the molding composition at any time during the curing cycle should be below the temperature at which any of the rc-~inine 11 raw materials or intermediate products violatilizes or 12 decomposes to products which yield poor physical 13 characteristics, eg., voids or discoloration.
14Among suitable curing agents acting at elevated temperatures are benxoyl peroxide, 2,5-dimethyl-2,5-bis 16 (2-ethyl hexyl peroxy) hexane, t-amyl peroxyoctoate, t-butyl 17 peroxyoctoate, lauroyl peroxide, t-butyl peroxybenzoate, 1,1 18 bis-t-butyl peroxy cycloheY~ne, l,l-bis-t-amyl peroxy 19 cyclohex~ne, and dicuml peroxide. Best results have been 20obtained with 2,5-dimethyl-2,5-bis (2-ethylhexanoylperoxy) 21 hexane and l,l-di-t-butyl peroxy-3,3,5-trimethylcyclohexane, 22 available from Akzo Chemicals as Trigonox ~41 and Trigonox 23 29-B75, respectively. Preferably a mixture of these two 24 curing agents in a weight ratio of from about 2:1 to about 1:20 is employed. The most appropriate ratio for any 26 particular resin-filler composition of this invention is a 27 function of the size and configuration of the mold and the * Trade~arXs ~ ~7 ~ 7 ~

1 heat transfer capabilities of the mold, and can be determined 2 by simple trial and error. Most preferably the ratio of the 3 two curing agents is between about 1:2 and about 1:4 for 4 products up to about 1/2 inch in thickness, and between about 1:4 and 1:20 for products greater than about 1/2 inch in 6 thickness, respectively.
7 Admixed with such components may be such additives well 8 known to those skilled in the art as colorants (including 9 organic and inorganic tinting agents, pigments, dyes, and metallic flakes), anti-settling agents, W stabilizers or 11 absorbers, antioxidants, fire retardant agents, viscosity 12 control agents etc. Suitable W stabilizers include 13 o-hydroxyphenyl benzotrizoles, such as 2-hydroxyphenyl 14 benzotriazole and 2-hydroxy 4-alkoxy benzophe~ones, and benzophenone, salicylates, cyanoacrylates, benzylidene, 16 malonates, and ox~lAnilides. Expecially preferred is 17 2-(2-hydro 3,5 di-t-amyl phenyl benzotriazole, available as 18 Tinuvin 328 from Ciba Geigy. Especially preferred for the 19 promotion of homogeneity and retarding settling of fillers are such thixotropic agents as organoclays (such as TIXOGEL
21 PL-S, sold by United Catalysts Inc.) and fumed silica (such 22 as CAB-O-SIL, sold by Cabot Corporation). Typically, only 23 small amounts, if any, of such constituents are required.
24 Suitable colorant concentrations are from about 0.05% to about 2%, based on the weight of the entire composition.
26 Suitable thixotropic agent concentrations are from abou,t 0.1%
27 to about 2%, based on the weight of the entire composition.

* Trade~ark B

1 Referring to Fig. 1, measured quantities of the 2 polyester resin, ethylenically unsaturated ~r- -r, and 3 filler are mixed together in a mixing tank 1. The additives, 4 if desired, and curing agents, may also be added to the mixing tank. Alternatively, curing agents, colorants, and 6 other additives can be introduced into the process stream, as 7 by in-line injection or mixing tank, at any convenient 8 location between the mixing tank 1 and the mold 6. It is 9 preferred that such constituents be added to the mixing tank, to assure proper portions of ingredients and thorough 11 mixing. Most preferably, the mixing tank is equipped with a 12 high speed dispersing blade (eg., from Ho~ er Equipment 13 Corp., Harrison, N.J., or from Morehouse Industries, Inc., 14 Fullerton, CA) to create a high shear environment to disaggregate any agglomerated filler particles, to intimately 16 coat the individual particles with resin, and to provide a 17 generally uniformly dispersed blend of materials.
18 From mixing tank 1 the admixture is then de-aerated, 19 either in the mixing tank 1, as by applying a vacuum to the tank, or in a separate de-aeration device. In Fig. 1, the 21 admixture is transferred by any convenient means to a 22 de-aerating device, exemplified in Fig. 1 as hopper 3.
23 Referring to the drawings, with valve a closed and valve b 24 open, transfer can be accomplished by pump 2. With valve a open and valve b closed, transfer can be accomplished by 26 suction (by creating a partial vacuum in hopper 3), by 27 gravity (by elevating tank 1 above hopper 3), or by pressure 202~507 1 fed (by pressurizing tank 1) or a combination thereof. The 2 admixture flows through pipe 11 into the top of hopper 3, in 3 which a partial vacuum is maintained by the continuous 4 operation of a vacuum pump. The ;nc- ing material is immediately fragmented or exploded by the expansion and 6 outflow of entrained air and falls as airless particles to 7 the bottom of the hopper 3. Once de-aeration is complete, 8 the de-aerated material may be transferred to mold 6 through 9 pump 4 and mixing device 5, through pump 4 alone, or directly to mold 6, as shown in Fig. 2, Fig. 4, and Fig. 3, 11 respectively, as explained more fully below.
12 It is preferred that the reaction mixture pass through 13 at least one filter prior to entering mold 6, to ensure that 14 undesired matter be removed prior to molding. It is especially preferred that two filters, 21 and 23, be employed 16 as shown in Fig. 1. Such filters may be of any conventional 17 type, preferably capable of removing particles of at least 50 18 microns in size, and preferably as small as 30 microns in 19 size. Bag filters are especially preferred. Of course, such filters cannot be employed when making a granite product 21 cont~ining chips larger than the filter size, since the 22 filters would remove the chips from the reaction mixture.

23 As shown in Fig. 2 in dotted lines, the uncatalyzed 24 reaction mixture is transferred by pump 4 through mixing device 5, wherein curing agent is injected by pump 7, to mold 26 6, with valves c and e closed and valve d and f open. The 27 transfer can be accomplished by pump 4 alone, or by blocking - 2027~07 1 the inlet to hopper 3 and thereafter pressurizing hopper 3.
2 In the latter case, the pressure is typically between about 8 3 psi and 40 psi. tIf pump 4 is a double diaghram pump, hopper 4 3 should not be pressurized, since its efficiency would be decreased).
6 As shown in Fig. 3 in dotted lines, the catalyzed 7 reaction mixture is transferred from hopper 3 directly to 8 mold assembly 6 through open valve c (valves d and e being 9 closed), as by pressurization of hopper 3 to between about 40 psi and about 100 psi. In Fig. 4, as show in dotted lines, 11 the catalyzed reaction mixture is transferred from hopper 3 12 to mold assembly 6 by pump 4, valve c being closed and valves 13 d and e being open. The mixture is r~? ' ved from hopper 3 by 14 pressurizing hopper 3, or by pump 4.
Pump 4 may be any convenient type of pump (driven by any 16 convenient means such as air or hydraulic pressure, 17 ~ch~nical or electrical means), such as a volumetric piston 18 pump, double diaphragm, or sine pump, all of which are 19 commercially available. The pump should be capable of pumping liquid without the re-incorporation of air into the 21 mixture and without generating substantial heat. Preferred 22 is a double diaphragm pump, such as the Sandpiper pump from 23 Warren Rupp Houdaille, of Mansfield, Ohio. Such a pump is 24 especially desired when the composition contains discrete chips as in the manufacture of granite or onyx, which could 26 abrade or block other types of pumps.

2027S~7 1 The pumping rates are such that the system is kept full 2 of the mixture, and thus free of air, until the mixture is 3 delivered into the cavities of mold 6. Substantial amounts 4 of entrained air would create voids in the molded product and at its surface, creating undesirable visual and physical 6 characteristics.
7 The curing agent may be either mixed directly with the 8 reaction mixture in mixing tank 1, or may be added to the 9 reaction mixture by a metering pump at some point during processing. The former method is most appropriate to batch 11 operations, in which the appropriate proportions of reaction 12 mixture and curing agent are measured into mixing tank 1. An 13 advantage to this method of curing agent addition is that it 14 is not dependent on the accuracy of a metering pump.
Regardless of where curing agent is introduced to the 16 reaction mixture, the initiation temperature should be 17 sufficiently high to avoid substantial curing within the 18 lines prior to entry into the mold.
19 One method of in-line curing agent introduction is illustrated in Fig. 2, in which dotted lines are intended to 21 show the flow from hopper 3 to mold assembly 6. The 22 uncatalyzed reaction mixture is transferred from hopper 3 23 through valve d (valve c being closed) and is further 24 transferred by pump 4 through valve f (valve e being closed) into mixing device 5. The curing agent is pumped via pump 7 26 through pipe 13 to the mixing device 5.

1 Mixing device 5 may be any convenient ~-h~ni~ for 2 thoroughly mixing the reaction mixture ~ ~,-rsnts without 3 introducing substantial amounts of air into the mixture. For 4 example, a tank with a rotating impeller or iYing blade, or a static mixer, are appropriate. The former is preferred 6 when mixing compositions cont~;ning chips which might block a 7 static mixer. Static mixers are preferred for compositions 8 without chips, such as the composition described above for a 9 homogenous marble-like product.
Static mixers have a means for the flowing material to 11 divide and recombine and either a plurality of angularly and 12 longitu~in~lly spaced, obliquely disposed vanes or a 13 plurality of plugs each pierced by a plurality of obliquely 14 disposed bores. Such devices are conventional in the art.
Pump 7 is a metering pump, electronically or 16 mechanically controlled (or synchronized) with pump 4 to 17 deliver the appropriate proportion of curing agent to mixing 18 device 5. From mixer 5, the curing agent passes into the 19 mold via line 9. Thus, pump 7 introduces, though mixer 5, a minor, but accurately metered, portion of curing agent into 21 the mixture. This method poses less of a risk of 22 catalyzation within the processing lines and equipment when 23 using a promotor or catalyst with a low initiation 24 temperature, since the curing agent is injected immediately prior to the mold. However, the metering pump 7 must be 26 sufficiently precise to continuously introduce the 2027~07 1 appropriate proportion of curing agent into the reaction 2 mix.
3 An alternative method of in-line curing agent injection 4 is shown in Fig. 4, in which the appropriate proportion of curing agent is injected by pump 7 through mixer 5 into the 6 reaction mixture as it flows through line 11 before it enters 7 hopper 3. The complete reaction mixture can be deaerated in 8 hopper 3.
9 Fig. 5 represents yet another variation on the method of this invention. To produce product of different colors from 11 one large master batch, the admixture from mixer 1 can be 12 transferred to one or more color mixing vessels. Fig. 5 13 shows two such vessels, la and lb, although any number of 14 color mixing vessels could be employed. The admixture is transfered from mixer 1 to color mixing vessels la and lb, in 16 which different colorants are added in the desired amounts.
17 The resulting admixture from vessel la or lb, or from both la 18 and lb, is then processed in the same manner as described 19 above. A single hopper 3 may be employed, or a separate hopper may b~ dedicated to each color to reduce the amount of 21 rle~n~lr reguire between runs of different colors.
22 Mold 6 i8 for forming sheet or panel material and has an 23 inlet valve assembly 8 at the lower end of one side adapted 24 to receive the admixture from pipe 9. At the upper end of an opposing side of said mold a riser means 10 is provided to 26 vent the mold.

20275~7 1 The mold assembly 6 for making sheets is a demountable 2 structure preferably comprising a plurality of mold cavities 3 with elevated vent ends. The vent is above the fill port and 4 is higher than any portion of the mold. The platens defining the assembly have a means for regulating the temperature 6 within the molding cavity.
7 Referring to Fig. 6, the apparatus comprises a removable 8 boundary frame 12, each side of which is bounded by a pair of 9 platens 14, which together define a mold 58. Although the mold shown in the drawings is rectangular, the platens having 11 planar surfaces to produce planar sheets or panels, the mold 12 size and configuration is a matter of choice depending on the 13 desired size and configuration of the molded product. The 14 platens 14 serve to define a portion of mold cavity 58, and also to transfer heat to and from the mold composition.
16 Means for applying heat to the composition within the mold is 17 provided, such as by electrical resistance heaters or 18 ~h~nnels within the platens for circulating heating fluid, or 19 any other convenient means. Preferably, means are also provided for cooling the composition once at least partial 21 cure has been accomplished. The preferred platens are 22 internally characterized by a plurality of heat transfer 23 rh~nnels (eg., tubes or cut-outs) through which, via fluid 24 entry ports 15, heating or cooling media, such as water or oil, as desired, can flow in order to uniformly heat and cool 26 the platen surface which is in contact with the resinous 27 composition. After the resinous composition has been 2~27S07 1 sufficiently cured, the platens are cooled by a cooling media 2 by introducing coolant through fluid entry ports 15. The 3 mold assembly of this invention thereby provides direct heat, 4 efficient, uniform heat transfer to and from the resinous composition.
6 Preferably, the fluid entry ports 15 are located in the 7 bottom perimeter portion of the platen 14 to allow heating or 8 cooling media to enter. These ports may optionally be 9 connected by a manifold to aid in directing the heat transfer media into the ports 15. Fluid exit ports 16 are preferably 11 in the top perimeter portion of the platen 14, wherein the 12 thermal regulating media exits the platen 14. These ports 16 13 may also be connected to an exit manifold to carry off the 14 media to a heating and cooling device not shown so that the fluids may be recycled if desired. Although in Fig. 6 only 16 two inlet ports 15 and outlet ports 16 are shown, 17 representing two zones of heat transfer, for molds above 8 18 feet long it is preferred to employ a minimum of four zones 19 to increase uniformity of temperature on the platen face in contact with the molding composition. It is also preferred 21 that each entry port 15 c~ lnicate with only one exit port 22 16, to allow more precise regulation of the temperature of 23 the mold.
24 The platens and their internal heat transfer chAnnels or tubes are preferably made of metal such as steel or 26 aluminum. The heating fluid is preferably water adjusted to 27 the desired temperature, preferably in excess of 150~F.

1 Cooling is effected by injecting cooling fluids into entry 2 port 15.
3 As shown in Fig. 6 and Fig. 11, the mold assembly is 4 preferably characterized by a plurality of removable boundary frames 12, defining the perimeter of molds 58, interleaved 6 between platens 14, defining the sides of molds 58, to 7 provide a series of molds 58, in order to more expeditiously 8 produce the desired number of panels. The boundary frames 9 may be of any convenient size, thickness, and shape. They can be non-linear to yield non-rectangular (eg., oval) mold 11 configurations. The boundary frames 12 are preferably made 12 of a light material for ease of handling, such as all i n or 13 a plastic such as polyethylene, polypropylene, nylon, or any 14 plastic with unaffected by the molding composition or the temperatures of the mold. Alternatively, the boundary frames 16 may be integral with the platens, as by being affixed to one 17 or more platens, or being formed as an extension or 18 depression in one or more platens. The boundary frame 12 may 19 also be made of a compressible material, such as pressurized tubing, to allow the platens to move as the molding 21 composition cures and shrinks, thereby keeping the platens in 22 contact with the molding composition during the entire curing 23 process. Heat transfer is thereby facilitated, and 24 conformity of the molded product with the mold is enhanced.
The mold assembly is supported as a unit on frame 18 26 with any convenient means, such as motors or air or hydraulic 27 pistons 17, for moving the platens 14 and boundary frames 12 - 28 ~

1 into abutting relationship with each other along tracks 19, 2 to form molds 58 between boundary frames 12 and platens 14.
3 Once the molds are filled and the reaction mixture is 4 partially or fully cured to a solid state, the platens, now defining the opposite sides of the molded panels, are 6 withdrawn along tracks 19 to facilitate removal of the 7 boundary frames, now defining the perimeters of the molded 8 products. Other views of the platen-frame assembly are shown 9 in Fig. 7 and Fig. 10.
A mold release agent is preferably employed, to 11 facilitate removal of the molded product from the mold. The 12 mold release agent must be compatible with the molding 13 composition, and stable at the temperature of the mold.
14 Release agents such as polyvinyl alcohol, fluoroplastic, oils, soaps, waxes, and silicones may be employed. The 16 preferred release agent is a highly polymeric synthetic resin 17 dissolved or suspended in a volatile organic solvent, which 18 leaves a slightly oily film upon evaporation of the solvent.
19 The release agent may be applied by any convenient means, eg., brush, -oller, or spray.
21 The molded product can be provided with a variety of 22 textures by employing press plates 22 between boundary frame 23 12 and platens 14, as illustrated in Fig. 14. Preferred are 24 press plates of the type employed in manufacturing high pressure decorative plastic laminate, ie., metal sheets. The 26 press plates can be embossed to produce an embossed or 27 textured finish on the molded product. Besides providing a 1 variety of surfaces, employment of removable press plates 2 facilitates cleaning the mold cavity, since when press plates 3 are employed reaction product does not contact the platens.
4 Alternatively, press plates of other materials, such as plastic sheets or films, or metal foils, can be employed.
6 Such a press plate comprises either rigid plastic sheets, or 7 thin flexible plastic film. The material must be compatible 8 with the reaction mixture, eg., it must not be affected 9 chemically by the mixture, and the temperatures during molding. Plastic film, such as 1 to 3 mil polyethylene, 11 expands upon the application of heat during curing, creating 12 an embossed slate-like surface finish to the molded product.
13 A heat-shrinkable film, such as 50-125 gauge Cryovac MPD 2055 14 or D955 (W.R. Grace ~ Co., Duncan, S.C.), shrin~s upon application of heat, yielding a smooth finish to the surface 16 of the molded product. Besides the ability to produce a 17 variety of surface finishes on the molded product, thin films 18 facilitate cleanup, since they are disposable, and have 19 release characteristics which eli in~te the use of a separate release agent. If provided in the form of bags, with inlet 21 and outlet openings corresponding to the inlet and outlet 22 ports of the mold, cleanup is further facilitated since no 23 molding composition will contact the platens or boundary 24 frames.
As shown in Fig. 13, the uppermost end of the top side 26 member of each mold has an upwardly exte~ding~ relatively 27 small rectangular riser projection 54 formed in it of which * Trademark 20~7507 1 one upright side member 20 is an extension of the adjacent 2 upright end member 56 of the boundary frame as a whole. A
3 plurality of small outlet passages 57 are formed in the top 4 side member of the boundary frame and provide for flow of material from within the cavity 58 defined by the boundary 6 frame 12 into the cavity 59 defined by the riser projection.
7 The side member 20 of the riser projection is pierced by at 8 least one, but preferably two, vent holes 60 and 61 disposed 9 one above the other. The issuance of material from a vent hole indicates that the corresponding mold cavity has been 11 completely filled to the level of the vent hole in question.
12 A clear riser pipe can be extended from the vent hole, 13 through which exiting material can be viewed, to avoid 14 spillage of material as it exits the vent hole. Through the riser can also be placed a thermocouple wire for monitoring 16 the temperature of the composition during the curing cycle.
17 In practicing the invention, it is preferred that the 18 respective mold cavities be filled as described hereinafter 19 until material issues from the lower vent hole 60 of each riser 54. As material reaches each lower vent, both vents of 21 the corLespon~ing riser structure are plugged by plugs 62 and 22 63 to prevent further flow into the corLe3pon~ing cavity.
23 Filling is then stopped, and all vents are plugged. Where 24 the mold assembly has more than one cavity, the next cavity is then similarly filled with the resinous composition.
26 A valve assembly 8 is provided to control the flow of 27 reaction mixture into the molds. As can best be seen in Fig.

1 12, the bottom end of the lower most member of each boundary 2 frame 12 has an inlet port block 64, which port block has one 3 or more inlet ports to allow the flow of the reaction mixture 4 through the boundary frame and into the mold cavity defined by it and the platens. Valve block 65 is connected to port 6 block 64 through pin 66, about which valve block 65 can 7 pivot. Valve block 65 has a tube 67 defining an opening in 8 communication with the inlet port(s) of port block 64 when 9 valve block 65 is pivoted to a first position, and which opening is not in communication with the inlet port(s) of 11 port block 64 when valve block 65 is pivoted to a second 12 position. Valve block 65 has a slot 68 through which stop 69 13 projects, to define said first and second pivot positions.
14 Other valve means are obvious. In addition, conventional valve means may be employed. An advantage of the valve means 16 of this invention is its simplicity, in that it has few 17 moving parts and is easily disassembled for cleaning and 18 repair.
19 The thermosettable compositions of this invention may be fully or partially cured in the mold described herein.
21 Preferably, the composition is brought to approximately 70X
22 to 90% of its completely cured state in the mold, which 23 generally occurs approximately 1 to 15 minutes after the 24 composition reaches its ~xi- temperature, or peak exotherm. The peak exotherm can be measured by a 26 thermocouple wire inserted into the reaction mixture, and can 27 be determined for any reaction mixture, catalyst composition, 1 and heat transfer fluid temperature. For example, one 2 convenient laboratory method comprises monitoring the 3 temperature profile over time of a sample quantity of the 4 molding composition placed in a water bath of constant temperature.
6 At a cure of from about 70% to about 90%, the 7 composition is semi-solid, or rubbery, with sufficient 8 dimensional stability to allow h~n~l ing. Removal of the 9 composition from the mold prior to complete cure allows the mold to be used for production of another panel, while the 11 partially cured material may be fully cured through other 12 means described below.
13 When the molding composition is introduced into the 14 mold, the mold temperature should be below the activation temperature of the curing agent. During curing, a heat 16 transfer fluid is circulated through the platens to maintain 17 a mold temperature between about 100~ F and 350~ F, and 18 preferably between about 150~ F and 220~ F. The fluid 19 serves to transfer heat to the molding cc ssition at the beginning of the curing cycle. Because the polymerization 21 reaction is exothermic, the temperature of the molding 22 c ~ tion may eventually exceed the temperature of the heat 23 transfer fluid, which then functions as a coolant to moderate 24 the rate of reaction. For molded products greater than about 1 inch in thickness, lower temperatures are desirable to 26 prevent thermal cracking.

2027~07 1 Within about 1 to about 15 minutes after the peak 2 exotherm is reached (after about 20 minutes to about 40 3 minutes in the mold), cooling water at between about 40~F
4 and about 100 F, and preferably between about 60~F and 80~F, is circulated through the molds to cool the molded 6 composition to between about 100~F and about 200~F, so 7 that it may be removed from the molds in at least a 8 semi-solid state. With the preferred composition of this 9 invention, the partially cured product exhibits a Barcol hardness of about 15 to 20 if removed from the mold one 11 minute after the peak exotherm is reached. At such a state 12 of cure, the product resembles hard rubber.
13 The molding composition can be fully cured and cooled in 14 mold 6. However it is preferred to remove the partially cured product from mold 6 prior to full cure. Subsequent to 16 removal from the press, the composition, if partially cured, 17 is transferred to a heated oven maintained at between about lô 100~F and about 300~F, and preferably between about 19 150~F and about 200~F, and so maintained for approximately 15 to 30 hours, and preferably about 24 hours, 21 to complete the curing process.
22 Alternatively, in lieu of use of a heated oven, after 23 removal from the mold 6 the partially cured composition may 24 be transferred to a curing press and maintained at between about 100~ F and about 300~ F, and preferably between 26 about 150~F and about 200~F, for between about 10 minutes 27 to about 1 hour for final curing. The curing press is 1 similar in design to the platen assembly shown in Fig. 9, 2 comprising heatable opposed platens. It is preferred that 3 curing in mold 6 be sufficiently complete that boundary 4 frames are not required for subsequent curing. The fully cured molded composition upon removal from the oven or curing 6 press may not be completely rigid, and may be relatively 7 pliable at the temperatures of the oven or curing press, if 8 the composition has not been cooled to below about 100~F.
9 It is preferred that the molded composition be transferred to a cooling press of a design similar to the platen assembly 11 shown in Fig. 9 and the curing press, except that means for 12 heating the composition are not required. The cooling press 13 should be maintained at between 40~ F and 100~ F for a 14 time sufficient to cool the composition to a rigid state.
Since the cured product as it is introduced to the oven, 16 curing press, or cooling press may not be completely rigid, 17 any texture and configuration of the support means in the 18 oven or presses (eg., the press platens) may be transferred 19 to the panels. If a completely smooth finish is desired, the support means should be completely smooth. Alternatively the 21 support means may bear a texture or design. In addition, 22 because of its lack of complete rigidity if only partially 23 cured in mold 6, the molded product can be further molded 24 into a variety of shapes in the curing press and/or cooling press, if desired, eg., the shape of a countertop with an 26 integral backsplash and/or integral apron.

2027~07 1 Use of separate devices for -l~ine, final curing, and 2 cooling is preferred to performing full curing and cooling in 3 mold 6. In the former case, each device can be kept at or 4 near its optimal temperature, without heating and cooling 5 cycles. In addition, the curing press or oven and the 6 cooling press are less complex, and less costly, than the 7 molds 6, and allow molds 6 to be available a greater portion 8 of the time.
9 The process and apparatus of this invention may further be employed in the production of articles simulating 11 granite. In this alternative embodiment, the cured synthetic 12 resinous material (chips) which may be obtained from the 13 process of this invention, is ground and then admixed with 14 the raw virgin components including curing agent in mixing 15 tank 1. It is preferred to mix all components, other than 16 the chips, in a high shear mixer as noted above, and to then 17 admix the chips using a low shear impeller, such as a 18 propeller blade, to avoid fracturing the chips.
19 Examples 21 A marble-like composition was prepared. The following 22 constltuents were admixed in a mixing tank, employing a 23 Morehouse Cowles dissolver model J25-2 ( see, U.S. Patent No.
24 3,135,499) equipped with a dispersing impeller to create high 25 shear mixing:
26 PARTS BY WT.
27 Polyester A 16.48 28 Styrene 7.06 29 Methyl methacrylate 9.36 5 ~ ~

1 THIXOGEL PL-S 0.35 2 Alumina trihydrate 66.55 3 TiO2 (70% in polyester) 0.20 4 Polyester A is a conden~ation product of neopentyl glycol, isophthalic acid and maleic anhydride. A combination 6 of polyester A and styrene is available c ~lly as a gel 7 coat resin for surface applications. The methyl methacrylate 8 in this and in all other examples contained 100 ppm methyl 9 ethyl hydroquinone inhibitor. The colorant, titanium dioxide, was in a ~rl- cr-free, low viscosity unsaturated 11 polyester, in a 70% by weight concentration.
12 Alumina trihydrste (ATH) was #308 from Sumitomo Chemical 13 Co., prepared by precipitation, to yield generally round 14 particles of about 8-10 micron mean particle diameter, with 0.1% greater than 44 microns, and 25% less than 4 microns.
16 Once thoroughly mixed to reach a temperature of about 17 100~F (approx. 1/2 hour), the mixture was cooled at room 18 temperature to about 80~F, and 1% (based on reactive resin 19 - polyester, styrene, MMA) of a 1:3 blend by weight of Trigonox 141 and Trigonox 29-B75 was admixed. The blend was 21 pumped through a bag filter having a screen size of about 150 22 microns, to the top of a vacuum tank at a vacuum of approx.
23 28 inches mercury, via a Moyno pump at the rate of 24 approximately 7.5 gallons/minute. Upon entering the vacuum tank, the mixture exploded, entrained air was removed, and 26 the de-aerated mixture fell to the bottom of the tank. The 27 de-aerated mixture was transferred by a piston pump from the 28 tank through a bag filter having a screen size of 50 microns ~ 37 -- * Trademark 1 to a mold as shown in Fig. 2, with a rectangular cavity 3 2 feet by 8 feet by 1/2 inch. The platens had four zoned heat 3 transfer sections, each with individual fluid inlet and exit 4 ports. The platens were continuously heated with 195~ F
water. The temperature of the composition was monitored via 6 a thermocouple wire inserted into the composition through the 7 exit port of the mold. The temperature of the molding 8 mixture reached its peak exotherm temperature of about 250~
9 F in approximately 20 minutes, and then began to decrease.
Approximately three minutes after the composition reached its 11 peak exotherm, cooling water at about 75 F was substituted 12 for heated water, and the panels were cooled to about 100~
13 F. The partially cured panels were removed from the mold, 14 and yielded a Barcol hardness of about 30. The panels were 15 then transferred to an oven, placed in a horizontal position, 16 and maintained at approximately 160~F for approximately 24 17 hours for final curing. The panels were then removed from 18 the oven and allowed to cool to room temperature. The 19 surface was wet sanded to obtain a satin finish. The cured 20 product appeared uniformly white, had consistent dimensions 21 correspo~ing to the mold cavity, and exhibited a uniform 22 Barcol hardness value of approximately 60. The molded sheet 23 had smoke and flame indices, measured by the ASTM E-84-87 24 test, of less than about 25. Other physical properties (such 25 as stain resistance, steam resistance, radiant heat 26 resistance, impact resistance, resistance to deflection under 1 heat and load, and breaking strength) were consistent with 2 commercial requirements.
3 Example 2 4A granite-like composition was prepared. Chips were prepared by grinding a sample of the marble product obtained 6 in Example 1. The chips were of a particle size distribution 7of between about 150 microns and 1800 microns, with a mean 8 particle size of about 800 microns. The matrix was prepared 9 from the following formulation, in the same manner as in Example 1 above :
11PARTS BY WT.
12 Polyester A 16.51 13 Styrene 7.07 14 Methyl methacrylate 9.38 THIXOGEL PL-S 0.35 16 Alumina trihydrate 66.69 17 Note that the above formulation is the same as in Example 1, 18 except that no colorant was used, in an effort to obtain a 19 generally color-free matrix for the synthetic granite product. The above matrix constituents were dispersed using 21 a high shear blade in a Cowles disperser until a temperature 22of about 100~F was reached (approx. 1/2 hour). A low shear 23 propeller blade was substituted for the high shear disperser 24 blade in the mixing tank, and to the matrix mixture was added about 12X by weight (based on the weight of the resulting 26 mixture) of chips. The resulting mixture was then mixed at 27 low shear until a thoroughly mixed generally homogeneous 28 blend was obtained (approximately one-half hour).
29The mixture was cooled at room temperature to about 80 F, and 1% (based on reactive resin - polyester, styrene, ~ 39 ~

1 methyl methacrylate; excluding resin in the chips) of a 1:3 2 blend by weight of Trigonox 141 and Trigonox 29-B75 was 3 admixed.
4 The mixture was then transferred to the top of a vacuum tank at a vacuum of 28 inches of mercury, via a double 6 diaphragm pump at the rate of approximately 7.5 7 gallons/minute. The pressure in the vacuum tank was 8 increased to atmospheric pressure and the de-aerated mixture 9 was pumped, by a double diaghram pump, from the bottom of the vacuum tank into a mold of the type described herein. No 11 in-line filters or static mixers were employed.
12 The mixture was cured in the mold and in an oven, in the 13 same manner as described in Example 1. The resulting molded 14 product comprised a generally white semi-translucent matrix with visually distinct white particles dispersed uniformly 16 throughout. The Barcol hardness values and the smoke and 17 flame indices for the product of Example 2 were the same as 18 in Example 1. Impact resistance was approximately one-half 19 that of the product of Example 1, and breaking strength was about 65% that of the product of Example 1. Other physical 21 properties were approximately the same as in Example 1.
22 Example 3 23 A second synthetic granite composition was prepared, 24 using chips having a different composition than the matrix.
A chip composition was prepared and cured, ground into chips, 26 and mixed with a matrix composition, which was thereafter 27 cured.

1The chip composition was prepared by admixing in a 2 mixing tank, employing a Cowles disperer with a high shear 3 impeller, the following composition:
4PARTS BY ~.
Polyester B 14.9-6 Styrene 7.4~
7 Methyl methacrylate 7.48 8 Alumina trihydrate 69.86 9 Carbon black 0.21 10Polyester B is a cond~nc~tion product of ethylene 11 glycol, isophthalic acid, and maleic anhydride. Polyester B
12 is c~ --Iy used in applications in which chemical resistance 13 is desired. The colorant, carbon black, was in a 14~nc r-free, low viscosity unsaturated polyester, in a 20%
by weight concentration. The ATH was Solem SB 336, produced 16 by grinding such that about 5% of particles were greater than 1744 microns and 25Z of particles were smaller than 10 microns, 18 with a mean particle size of between about 14 and about 17 19 microns.
20The composition was prepared, catalyzed and cured in the 21 same manner as the composition of Example 1. The cured 22 composition was ground into chips in the same manner and of 23 the same size as in Example 2.
24A matrix composition was prepared in the same manner as set forth in Example 1, employing the following composition:
26PARTS BY WT.
27 Polyester A 17.31 28 Styrene 7.42 29 Methyl methacrylate13.82 THIXOGEL PL-S O.57 31 Alumina trihydrate 60.88 * Trade~ar]s 1 Polyester A is the same polyester as in Example 1. The ATH
Z was the same as in Example 1.
3 The synthetic granite product was prepared in the same 4 manner as set forth in Example 2, using the chips of this example and the matrix composition of this example. The 6 weight ratio of chips to matrix on the chips was the same as 7 in Example 2, ie., 12%. The same curing agent was employed, 8 in the same manner, as in Example 2. The molded product 9 comprised a generally white semi-translucent matrix with visually distinct black particles dispersed uniformly 11 throughout. The product also had the same smoke and flame 12 indices, and Barcol hardness, of the product of Example 2.
13 The breaking strength was about 75% that of the product of 14 Example 1, and the impact resistance was about 55% that of the product of Example 1. The other physical properties were 16 approximately the same as those of the product of Example 1.

18 A third synthetic granite composition was prepared, in 19 exactly the same manner as set forth in Example 3, with the same proportions of the same constituents, except that about 21 40X of the methyl methacryate was withheld from the matrix 22 composition and used to wet the chips prior to mixing them 23 with the matrix.
24 The total amount of methyl methacrylate in the resulting granite molding composition was 13.82% based on the weight of 26 the resulting composition excluding the weight of the chips.

1 In other words, the proportion of methyl methacrylate used in 2 the synthetic granite composition of this example was the 3 same as in Example 3.
4 The matrix composition, after substracting the methyl methacrylate' used to wet the chips, comprised the following:
6 PARTS B" WT.
7 Polyester A 18.,6 8 Styrene 7. 7 9 Methyl methacrylate 8.58 THIXOGEL PL-S 0.60 11 Alumina trihydrate 64.59 12 The product appeared substantially identical to that of 13 Example 3. The product had the same smoke and flame indices, 14 and B~rcol hardness, of the product of Example 3. The strength of the product was about 95% of that of the product 16 of Example 1, and the impact resistance was about 80X of that 17 of the product of Example 1. The other physical properties 18 of the product approximated those of the product of Example 21 A fourth granite-like composition was prepared, this 22 time using chips of substantially larger size than in the two 23 preceeding examples. The chips were prepared by grinding a 24 sample of the marble product obtained in Example 1. The chips were of particle size distribution between about 500 26 microns and 2000 microns, with a mean particle size of about 27 1500 microns. The matrix was prepared from the same matrix 28 formulation and in the same manner as in Example 3.
29 The chips were first coated with methyl methacrylate in the same amount and manner as in Example 4, and then combined ~ 43 ~

1 with the matrix in the same manner as in Example 2, with the 2 same curing agent as in Example 2, and was thereafter 3 processed in the manner set forth in Example 2. The chips 4 comprised 12% by weight of the matrix composition, including in the latter the methyl methacrylate on the chips (ie., the 6 same proportion as in Examples 2 and 3). The resulting 7 molded product comprised a generally white semi-translucent 8 matrix with large, visually distinct white particles 9 dispersed uniformly throughout. The Barcol hardness values and the smoke and flame indices for the product were the same 11 as for the product in Example 1. The strength of the product 12 was about 65% of the product of Example 1, and the impact 13 resistance was about 50% of the product of Example 1. Other 14 physical properties were about the same as the product of Example 1.
16 Example 6 17A fifth synthetic granite composition was prepared, 18 using a much smaller proportion of chips, and slightly 19 smaller chips, than in the preceeding example. The chips were ground from several marble products prepared as set 21 forth in Example 1, except that in place of titanium dioxide 22 each marble product had been prepared with a different 23 colorant employed at approximately the same concentration 24 (0.2% by weight of the matrix). The colorants were liquid colorants from PDI of Edison, N.J., comprising pigment at 26 from about 15% to about 70% by weight in a monomer-free, low 27 viscosity unsaturated polyester. The chips were prepared by 2~27S~7 1 grinding several samples of such marble products to yield a 2 particle size distribution of between about 500 microns and 3 1800 microns, with a mean with a mean particle size of about 4 1150 microns. The matrix was prepared from the same matrix formulation set forth in Example 2, in the manner set forth 6 in Example 2.
7 The chips were combined with the matrix in the manner 8 set forth in Example 2 (ie., without pre-wetting the chips 9 with methyl methacrylate) with the same curing agent as in Example 2. Only 2 1/2X by weight of chips, based on the 11 weight of the resulting mixture, was used. The resulting 12 mixture was thereafter processed in the manner set forth in 13 Example 2. The resulting molded product comprised a 14 generally off-white matrix with small, visually distinct particles of various colors dispersed uniformly throughout.
16 The Barcol hardness values and the smoke and flame indices 17 for the product were the same as for the product in Example 18 1. The strength of the product was about 85% of the product 19 of Example 1, and the impact resistance was about 60% of the product of Example 1. The other physical properties were 21 about the same as the product of Example 5.
22 Example 7 23 A sixth simulated granite product was prepared, in 24 exactly the same manner as in Example 6. except that about half of the methyl methacrylate from the matrix composition 26 was withheld from that composition and used to wet the chips 27 before they were added to the matrix composition. The chips 202~07 1 were mixed with the methyl methacrylate to thoroughly wet 2 them, and then the wet chips were added to the balance of the 3 matrix composition. The resulting molded product appeared 4 identical to the product of Example 6, and had the same Barcol hardness, smoke and flame indices as the product of 6 Example 6. The physical properties of the product were the 7 same as the product of Example 6.
8 Example ô
9 A second synthetic marble composition was prepared, employing styrene instead of methyl methacrylate. The 11 composition comprised the following:
12 PARTS BY WT.
13 Polyester A 16.48 14 Styrene 16.42 THIXOGEL PL-S O. 35 16 Alumina trihydrate 66.55 17 TiO2 (70% in polyester) O. 20 18 Polyester A is the same polyester as in Example 1.
19 The composition was processed, catalyzed, and cured in the same manner as in Example 1. The viscosity of the 21 composition was substantially higher than in the above 22 compositions employing methyl methacrylate. The Barcol 23 hardness was 55. The smoke index was about 30 and the flame 24 index was about 25. The physical properties approximated the product of Example 1.
26 Example 9 27 A third synthetic marble product was prepared, 28 substituting styrene for methyl methacrylate. The 29 composition comprised the following:
PARTS BY WT.

1 Polyester A 28.29 2 Styrene 15.23 3 Alumina trihydrate 56.31 4 TiO2 (70% in polyester) 0.17 Polyester A is the same polyester used in Example 1.
6 The composition was processed, catalyzed, and cured in 7 the same manner as in Example 1. The Barcol hardness was 8 about 55-60. The smoke index was 110 and the flame spread 9 index was 41. The physical properties approximated the product of Example 1.

12 A fourth synthetic marble composition was prepared, 13 employing styrene instead of methyl methacrylate and with a 14 different polyester resin. The composition comprised the following:
16 PARTS BY WT.
17 Polyester C 29.35 18 Styrene 15.80 19 Alumina trihydrate 54.64 TiC2 (70% in polyester) O. 20 21 Polyester C is a condensation product of ethylene glycol, 22 orthophthalic acid, and maleic anhydride.
23 The composition was processed, catalyzed, and cured in 24 the same manner as in Example 1. The Barcol hardness was 50-55- The smoke index was 240 and the flame index was 47.
26 The strength and impact resistance of the product 27 approximated that of the product of Example 1. The product 28 displayed poor heat distortion resistance.

A granite product was made using the matrix of Example 31 3' with chips between one-half inch and one inch in size.

202750~

1 The chips employed were made from the product of Examples 1 2 and 3. The chips were mixed with the matrix, without first 3 wetting the chips with methyl methacrylate, and with the same 4 curing agent in the same proportion as in Example 2. The chips comprised about 12Z by weight of the resulting 6 mixture. The resulting mixture was poured into a small pan 7 about 4 inches deep, 4 inches wide, and 8 inches long. The 8 mixture was cured in an oven at 100~F for about three 9 days. The cured product was cut with a bA~CAW into slices approximated 1/2 inch thick, and polished. The product had a 11 generally white semi-translucent matrix with large chips 12 dispersed throughout, small chips clearly visible in the 13 large chips. The physical properties of the product were not 14 tested, but are believed to be consistent with the properties of the product of Example 2.

17 A marble composition was made using a high loading of 18 large alumina trihydrate particles. The mean size of the ATH
19 particles was 70 microns, with 54% being above 74 microns and 90~ being above 44 microns. The molding composition was as 21 follows:
22 PARTS BY WT.
23 Polyester A 7.24 24 Styrene 3.10 Methyl methacrylate 4.11 26 THIXOGEL PL-S 0.35 27 Alumina trihydrate 85.00 28 TiO2 (70% in polyester)0.20 29 The product was made in the same manner as the product of Example 1, with the same proportion of the same curing 31 agent as in Example 1. The resulting molded product was ~ ~ 6A~ r~y 1 chalky, with poor stain resistance, strength, and impact 2 resistance.

4 The synthetic granite composition of this example was prepared in exactly the same manner as set forth in Example 6 6, using the same chips and other constituents, in the same 7 amounts, as in Example 6, except that instead of the curing 8 agent set forth in Example 6 a 1:3 weight ratio combination 9 of Percadox 16 and Trigonox 29-B75 was used. Percadox 16 is bis (4-t-butyl cyclohexyl) peroxy dicarbonate, available from 11 Akzo Chemie. The amount of curing agent used was 1% based on 12 the weight of the resin (other than that in the chips).
13 All properties of the composition of this example were 14 substantially the same as the product of Example 6.

16 The synthetic granite composition of this example is 17 prepared in exactly the same manner as set forth in Example 18 6, except that instead of the catalyst set forth in Example 6 19 Trigonox KSM is used. Trigonox KSM comprises 50% by weight t-butyl peroctoate, 25Z by weight 1,1, di-t-butyl-3,5,5 21 trimethyl cycloh~y~ne~ and 25% by weight dibuytl phthalate.
22 The amount of curing agent is lX based on the weight of the 23 resin, excluding chips. All properties of the composition of 24 this example are substantially the same as the product of Example 6.

B * Trademark 1 The synthetic granite cc osition of this example is 2 prepared in exactly the same manner as set forth in Example 3 6, except that instead of the catalyst set forth in Example 6 4 a 1:3 blend of Trigonox 141 and Trigonox 21-OP50 is used.
Trigonox 21-OP50 comprises 50Z by weight t-butyl peroxy 2 6 ethyl heXAnoAte or t-butyl peroctoate, and 50Z by weight 7 dioctyl phthalate. The amount of curing agent is 1% based on 8 the weight of the resin, excluding chips. All properties of 9 the composition of this example are substantially the same as the product of Example 6.

12 Various methods of post-mold curing were tested.
13 Several partially cured panels from Example 1 were placed in 14 an oven after removal from the mold, for various periods of time at various temperatures, instead of the 24 hours at 16 160~F of Example 1. Several other such partially cured 17 panels from Example 1 were placed in a curing press for 18 various periods of time, at various temperatures. Each of 19 the samples was then cooled to room temperature, and subject to a heat distortion test. The heat distortion test 21 comprised placing a 1" x 24" x 1/2" sample on a pair of knife 22 edges 16" apart, placing a lOlb weight on the center of the 23 sample, and placing the weighted sample in an oven at 150~F
24 for 24 minutes. The results were as follows:
Oven, 160~F, 6 hours 11/32"
26 Oven, 160~F, 24 hours 5/32n 27 Oven, 200~F, 2 hours 14/32"

1 Oven, 200~F, 6 hours 13/32"
2 Oven, 200~F, 24 hours 4/32"
3 Oven, 250~F, 2 hours 5/32 4 Oven, 250~F, 6 hours 4/32"
Oven, 250~F, 24 hours 4/32"
6 Press, 200~F, 5 minutes 19/32"
7 Press, 200~F, 15 minutes 5/32"
8 Press, 250~F, 5 minutes 8/32"
9 Press, 250~F, 15 minutes 6/32"
Press, 300~F, 5 minutes 3/32"
11 Press, 300~F, 15 minutes 5/32n 12 Each of the above samples had the same general 13 appearance, except that the products increased in yellowing 14 with increasing temperature. The other physical characteristics, Barcol hardness, and smoke and flame spread 16 indices of each of the samples was the same as the product of 17 Example 1.

19 A test WBS conducted to determine the effect of filler particle size distribution on the ability to load the molding 21 composition with filler. Two test batches were prepared of a 22 polyester - styrene - methyl methacrylate resin, one with 23 Alcoa C333 ATH, and the other with Acoa Hydral 710 ATH.
24 Alcoa C333 ATH has a median particle size of 8 microns, with 95% ~f particles less than 30 microns, 83% less than 20 26 microns, 58% less than 10 microns, and 35% less than 5 27 microns. Hydral 710 ATH has a median particle size of 1 * Trademarks ~.~

1 micron, with 95% less than 3 microns, 90% less than 2 2 microns, 20X less than 0.6 microns, and 10% less than 0.5 3 microns. The Alcoa C333 ATH was added to a test batch of 4 resin. The Hydral was added to a second test batch of resin. A blend of 80% by weight C333 and 20% by weight 6 Hydral was added to a third test batch of resin. All three 7 batches were made with the same wight precent of ATH. The 8 blend of C333 and Hydral had a lower viscosity than either of 9 the first two batches, indicating that a wider particle size distribution allows a greater proportion of ATH to be added 11 to the resin.

12 As is readily apparent from the above description 13 additional advantages and modifications will readily occur to 14 one skilled in the art. The invention in its broader aspects is therefore not limited to the specific examples shown and 16 described. Accordingly, departures may be made from the 17 details shown in the examples without departing from the 18 spirit or scope of the disclosed general inventive concept.

Claims (51)

1. A thermosettable molding composition comprising an intimately mixed and substantially airless mixture of a first portion comprising: between about 10 to about 25 parts by weight of a polyester comprising the reaction product of (i) at least one acyclic ethylenically unsaturated dicarboxylic acid or anhydride thereof (ii) at least one aromatic dicarboxylic acid and (iii) a C2-C8 glycol; between about 10 and about 25 parts by weight of an ethylenically unsaturated monomer; between about 50 and about 80 parts by weight of de-aggolomerated particles selected from the group consisting of alumina trihydrate, borax, hydrated magnesium, calcium carbonate and calcium sulfate dihydrate, said particles having a mean size of between about 5 microns and about 20 microns, and having a maximum size of about 50 microns and a minimum size of about 0.1 micron, said particles being substantially coated by said monomer and said polyester; and a second portion comprising: an amount of free-radical producing curing agent sufficient to substantially completely react said first portion, wherein said free radical producing curing agent comprises a first free-radical producing curing agent which is initiated at a temperature of between about 100°F and about 200°F
and a second free-radical producing curing agent which is initiated at a temperature of between about 150°F and about 300°F.

2. The composition of Claim 1 wherein said aromatic dicarboxylic acid isselected from the group consisting of phthalic acid and isophthalic acid.

3. The composition of Claim 1 wherein said acyclic ethylenically unsaturated dicarboxylic acid is selected from the group consisting of maleic acid, fumaric acid, linoleic acid, linolenic acid, itaconic acid, oleic acid, and anhydrides thereof.

4. The composition of Claim 1 wherein said glycol is selected from the group consisting of neopentyl glycol, 1,4-butanediol, 1,6-hexanediol, 1,4-cyclohexanediol, ethylene glycol, propylene glycol, dipropylene glycol, diethylene glycol, butylene trimethylene glycol, and triethylene glycol.

5. The composition of Claim 1 wherein said ethylenically unsaturated monomer is selected from the group consisting of alkyl acrylates, alkyl methacrylates, hydroxyalkyl acrylates, hydroxyalkyl methacrylates, N,N-dialkylaminoalkyl acrylates, N,N-dialkylaminoalkyl methacrylates, styrene, vinyl acetate, acrylonitrile, methacrylonitrile, maleic acid, maleic anhydride, maleic acid esters, acryl amide, methacrylamide, itaconic acid, itaconic anhydride, itaconic acid ester, alkylenediacrylate, alkylene dimethacrylates, N-hydroxymethyl-acrylamide, diallyl phthalate, divinylbenzene, vinyl toluene, divinyltoluene, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol tetraacrylate, pentaerythritol tetracrylate, triallyl citrate, and triallyl cyanurate and mixtures thereof.

6. The composition of Claim 5 wherein said alkyl acrylate is selected from the group consisting of methyl acrylate, ethyl acrylate, n-propyl acrylate, i-propyl acrylate, n-butyl acrylate, 2-butyl acrylate, i-butyl acrylate, t-butyl acrylate, 2-ethylhexyl acrylate, and cyclohexyl acrylate.

7. The composition of Claim 1 wherein said ethylenically unsaturated monomer is selected from the group consisting of styrene and methyl methacrylate.

8. The composition of Claim 1 wherein said ethylenically unsaturated monomer comprises styrene and methyl methacrylate.

9. The composition of Claim 8 wherein said styrene and said methyl methacrylate are in a weight ratio of between about 2:1 and about 1:4.

10. The composition of Claim 1 wherein the particle size distribution is such that smaller particles substantially fill the interstices between larger particles.

11. The composition of Claim 1 wherein the cured product has a Barcol hardness of at least about 55.

12. The composition of Claim 1 wherein said first curing agent is 2,5-dimethyl-2,5-bis(2-ethyl hexanoylperoxy) hexane and said second curing agent is 1,1-di-t-butyl peroxy-3,3,5-trimethylcyclohexane.

13. The composition of Claim 12 wherein the weight ratio of the first curing agent and the second curing agent is between about 2:1 to about 1:20.

14. A composition simulating granite or onyx comprising the cured product of an intimately mixed and substantially airless thermosettable molding composition comprising: between about 10 to about 25 parts by weight of a polyester comprising the reaction product of (i) at least one acyclic ethylenically unsaturated dicarboxylic acid or anhydride thereof (ii) at least one aromatic dicarboxylic acid and (iii) a C2-C8 glycol; between about 10 to about 25 parts by weight of an ethylenically unsaturated monomer; and between about 50 to about 80 parts by weight of a filler selected from the group consisting of alumina trihydrate, borax, hydrated magnesium, calcium carbonate and calcium sulfate dihydrate;
an aesthetically acceptable amount of discrete chips of an at least partially cured synthetic resin, said chips having a mean particle size of greater than about 50 microns; and an effective amount of a heat-initiated free-radical producing curing agent, wherein said free radical producing curing agent comprises a first free-radical producing curing agent which is initiated at a temperature of between about 100°F and about 200°F and a second free-radical producing curing agent which is initiated at a temperature of between about 150°F and about 300°F.

15. The composition of Claim 14 wherein said chips have a minimum particle size of about 50 microns and a maximum particle size of about 25,000 microns.

16. The composition of Claim 14 wherein said chips comprise between about1 percent and about 50 percent by weight of said composition.

17. The composition of Claim 14 wherein said aromatic dicarboxylic acid is selected from the group consisting of phthalic acid and isophthalic acid.

18. The composition of Claim 14 wherein said acyclic ethylenically unsaturated dicarboxylic acid is selected from the group consisting of maleic acid, fumaric acid, linoleic acid, linolenic acid, itaconic acid, oleic acid, and anhydrides thereof.

19. The composition of Claim 14 wherein said glycol is selected from the group consisting of neopentyl glycol, 1,4-butanediol, 1,6-hexanediol, 1,4-cyclohexanediol, ethylene glycol, propylene glycol, dipropylene glycol, diethylene glycol, butylene trimethylene glycol, and triethylene glycol.

20. The composition of Claim 14 wherein said ethylenically unsaturated monomer is selected from the group consisting of alkyl acrylates, alkyl methacrylates, hydroxyalkyl acrylates, hydroxyalkyl methacrylates, N,N-dialkylaminoalkyl acrylates, N,N-dialkylaminoalkyl methacrylates, styrene, vinyl acetate, acrylonitrile, methacrylonitrile, maleic acid, maleic anhydride, maleic acid esters, acryl amide, methacrylamide, itaconic acid, itaconic anhydride, itaconic acid ester, alkylenediacrylate, alkylene dimethacrylates, N-hydroxymethyl-acrylamide, diallyl phthalate, divinylbenzene, vinyl toluene, divinyltoluene, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol tetraacrylate, pentaerythritol tetramethacrylate, triallyl citrate, and triallyl cyanurate and mixtures thereof.

21. The composition of Claim 20 wherein said alkyl acrylate is selected from the group consisting of methyl acrylate, ethyl acrylate, n-propyl acrylate, i-propyl acrylate, n-butyl acrylate, 2-butyl acrylate, i-butyl acrylate, t-butyl acrylate, 2-ethylhexyl acrylate, and cyclohexyl acrylate.

22. The composition of Claim 14 wherein said ethylenically unsaturated monomer is selected from the group consisting of styrene and methyl methacrylate.

23. The composition of Claim 14 wherein said ethylenically unsaturated monomer comprises styrene and methyl methacrylate in a weight ratio of between about 2:1 and about 1:4.

24. The composition of Claim 14 wherein the particle size of said filler is between from about 0.1 to about 50 microns.

25. The composition of Claim 24 wherein the mean particle size is betweenabout 5 microns and 20 microns and the particle size distribution is such that smaller particles substantially fill the interstices between larger particles.

26. The composition of Claim 14 wherein said first curing agent is 2,5-dimethyl-2,5-bis(2-ethyl hexanoylperoxy) hexane and said second curing agent is 1,1-di-t-butyl peroxy-3,3,5-trimethylcyclohexane.

27. The composition of Claim 26 wherein the weight ratio of the first curing agent and the second curing agent is between about 2:1 to about 1:20.

28. A process for the molding of articles comprising:

combining a thermosettable resinous composition and a filler to yield a molding composition, wherein said resinous composition comprises:
between about 10 to about 25 parts by weight of a polyester comprising the reaction product of (i) at least one acyclic ethylenically unsaturated dicarboxylic acid or anhydride thereof (ii) at least one aromatic dicarboxylic acid and (iii) a C2-C8 glycol; between about 10 to about 25 parts by weight of an ethylenically unsaturated monomer;
between about 50 to about 80 parts by weight of a filler selected from the group consisting of alumina trihydrate, borax, hydrated magnesium calcium carbonate and calcium sulfate dihydrate; and an effective amount of a heat-initiated free-radical producing curing agent, wherein said free radical producing curing agent comprises a first free-radical producing curing agent which is initiated at a temperature of between about 100°F and about 200°F and a second free-radical producing curing agent which is initiated at a temperature of between about 150°F and about 300°F;
mixing said molding composition at high shear sufficient to de-agglomerate said filler and to substantially coat said filler with said resinous composition;
de-aerating said resultant mixed molding composition to yield a substantially airless mixtures;
transferring said mixture under substantially airless conditions to a substantially closed mold having means for regulating the temperature thereof; and at least partially curing the composition by heat to form a molded composition.

29. The process of Claim 28 wherein said molded composition is removed from said mold at between about 70 percent and about 90 percent cure.

30. The process of Claim 28 wherein said molded composition is removed from said mold at a Barcol hardness of between about 15 and about 30.

31. The process of Claim 28 wherein said mold comprises generally planar opposed platens having channels through which heat transfer fluid can be passed to regulate the temperature of the platens, and a boundary frame between said platens.

32. The process of Claim 31 wherein said boundary frame is compressible.

33. The process of Claim 31 wherein said mold further comprises press plates adjacent to said platens.

34. The process of Claim 34 wherein said press plates are non-metallic.

35. The process of Claim 31 wherein multiple pairs of platens are movablysupported by a frame, at least one of each pair of platens being movably supported by said frame, providing multiple molds.

36. The process of Claim 28 wherein said composition is partially cured, and thereafter maintained in a heating means maintained at between about 100°F and about 300°F for a time sufficient to produce a substantially cured composition.

37. The process of Claim 36 wherein said heating means comprises a curingpress.

38. The process of Claim 36 wherein said time is between about 15 and 30 hours.

39. The process of Claim 36 wherein the configuration of said partially cured composition is modified while in said, heating means.

40. The process of Claim 36 wherein said substantially cured composition is maintained in a cooling means between about 40°F and about 100°F for a time sufficient to cool the composition to a rigid state.

41. The process of Claim 40 wherein said cooling means comprises a cooling press.

42. The process of Claim 28 wherein said composition further comprises anaesthetically acceptable amount of discrete chips of a cured synthetic resin.

43. The process of Claim 28 wherein said aromatic dicarboxylic acid is selected from the group consisting of phthalic acid and isophthalic acid.

44. The process of Claim 28 wherein said acyclic ethylenically unsaturated dicarboxylic acid is selected from the group consisting of maleic acid, fumaric acid, linoleic acid, linolenic acid, itaconic acid, oleic acid, and anhydrides thereof.

45. The process of Claim 28 wherein said glycol is selected from the group consisting of neopentyl glycol, 1,4-butanediol, 1,6-hexanediol, 1,4-cyclohexanediol, ethylene glycol, propylene glycol, dipropylene glycol, diethylene glycol, butylene trimethylene glycol, and triethylene glycol.

46. The process of Claim 28 wherein said ethylenically unsaturated monomer is selected from the group consisting of alkyl acrylates, alkyl methacrylates, hydroxyalkyl acrylates, hydroxyalkyl methacrylates, N,N-dialkylaminoalkyl acrylates, N,N-dialkylaminoalkyl methacrylates, styrene, vinyl acetate, acrylonitrile, methacrylonitrile, maleic acid, maleic anhydride, maleic acid esters, acryl amide, methacrylamide, itaconic acid, itaconic anhydride, itaconic acid ester, alkylenediacrylate, alkylene dimethacrylates, N-hydroxymethyl-acrylamide, diallyl phthalate, divinylbenzene, vinyl toluene, divinyltoluene, trimethylolpropane triacrylate, trimethylolpropane trimethacrylate, pentaerythritol tetraacrylate, pentaerythritol tetramethacrylate, triallyl citrate, and triallyl cyanurate and mixtures thereof.

47. The process of Claim 46 wherein said alkyl acrylate is selected from the group consisting of methyl acrylate, ethyl acrylate, n-propyl acrylate, i-propyl acrylate, n-butyl acrylate, 2-butyl acrylate, i-butyl acrylate, t-butyl acrylate, 2-ethylhexyl acrylate, and cyclohexyl acrylate.

48. The process of Claim 28 wherein said ethylenically unsaturated monomer is selected from the group consisting of styrene and methyl methacrylate.

49. The process of Claim 28 wherein said ethylenically unsaturated monomer comprises styrene and methyl methacrylate in a weight ratio of between about 2:1 and about 1:4.

50. The process of Claim 28 wherein said first curing agent is 2,5-dimethyl-2,5-bis(2-ethyl hexanoylperoxy) hexane and said second curing agent is 1,1-di-t-butyl peroxy-3,3,5 -trimethylcyclohexane.

51. The process of Claim 50 wherein the weight ratio of the first curing agent and the second curing agent is between about 2:1 to about 1:20.